Network elements like base stations of mobile telecommunications networks are comparable to computers in terms of reconfiguration process. The reconfiguration process may comprise any type of hardware and software configuration changes. The reconfiguration process in mobile telecommunications networks typically includes software updates or updating radio network parameters such as radio frequencies or e.g. signal transmitting power. The reconfiguration may cause interference in the network, e.g. because of software incompatibilities or temporarily overlapping parameter values. Thus it is disturbing services offered in the network. The reconfiguration process may require a restart of the whole radio network, e.g. when a new radio frequency plan is activated in the network. Restarting base stations or any other network elements usually results in service breaks. Thus restarts should be scheduled to be executed at a time of low network load, e.g. at nighttime. The increased utilization of packet switched mobile services has however increased network load during nighttime also. This results in service breaks for even more subscribers.
A mobile telecommunications system, such as a GSM (Global System for Mobile communication) or a 3GPP (3rd Generation Partnership Project) system, comprises a cellular radio network. A cell refers to an area in which one base station is operable. Bounds of a cell are not constant because of e.g. changes in weather conditions. Base stations next to each other need to operate on different radio frequencies so that their cells will not interfere with each other because of overlapping. FIG. 1 illustrates cells overlapping each other. The overlapping in FIG. 1 is an example, thus the cells may overlap more or less depending on e.g. weather conditions and/or network design. The network uses four different radio frequencies in the example in FIG. 1. The frequencies are designated numbers 1-4. The cells are organized in such a manner that the same frequencies do not overlap each other.
In prior art a reconfiguration, such as e.g. a radio frequency change, has been applied simultaneously to several base stations in a cellular communication network such as a GSM network. Typically base stations are configured one base station controller at a time. That is, base stations controlled by a base station controller are reconfigured in a bunch. All the existing connections in the involved cells must be disconnected or handed over manually cell by cell for reset. New connections are not allowed while reset is being applied. These cause service breakdowns which disturb subscribers using the network during the reconfiguration.
The more base station controllers and base stations there exist in a network and the more base stations are configured at a time, the more complicated the procedure becomes. Thus a vast group of base stations requires an efficient system for reconfiguration.
Mobile telecommunications, GSM for example, has become more and more popular and the amount of mobile users has grown rapidly in the networks. Mobile operators must guarantee a quality of service both to their existing and new subscribers. That is why they must increase the capacity of their network. For example, a base station can serve only a limited amount of users at a time, thus new base stations need to be built for the network. New base stations may cause changes e.g. to the neighboring cells because the neighboring base stations need to use different radio frequencies. The changes in the neighboring cells may cause further changes to their respective neighbors and so on. Because of this the reconfiguration is a complex process. The more network elements like base stations have to be reconfigured in a given time, the more complex the system gets.
3GPP radio networks operate in higher frequencies than GSM networks. Therefore 3GPP networks require more base stations to cover the same geographical area. Base stations are reconfigured individually in 3GPP systems. This eliminates some of the drawbacks of the GSM network reconfiguration since the changes affect locally. However, the more base stations are reconfigured individually, the more time is needed for the reconfiguration. Changes to a whole network, e.g. software updates, typically require a service breakdown or a slow reconfiguration base station by base station.
The prior art methods for reconfiguration are complex and inefficient. A further drawback is a service breakdown, in some cases for the whole network. These cause unnecessary expenses to operators and extraneous disturbances for subscribers using the service while the network is being reconfigured. Thus there is an obvious need for an efficient method for reconfiguring mobile telecommunications networks.